CallbackDataSource.cpp revision 99f31604136d66ae10e20669fb6b5716f342bde0
1/* 2 * Copyright 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17//#define LOG_NDEBUG 0 18#define LOG_TAG "CallbackDataSource" 19#include <utils/Log.h> 20 21#include "include/CallbackDataSource.h" 22 23#include <binder/IMemory.h> 24#include <media/IDataSource.h> 25#include <media/stagefright/foundation/ADebug.h> 26 27#include <algorithm> 28 29namespace android { 30 31CallbackDataSource::CallbackDataSource( 32 const sp<IDataSource>& binderDataSource) 33 : mIDataSource(binderDataSource) { 34 // Set up the buffer to read into. 35 mMemory = mIDataSource->getIMemory(); 36} 37 38CallbackDataSource::~CallbackDataSource() { 39 ALOGV("~CallbackDataSource"); 40 mIDataSource->close(); 41} 42 43status_t CallbackDataSource::initCheck() const { 44 if (mMemory == NULL) { 45 return UNKNOWN_ERROR; 46 } 47 return OK; 48} 49 50ssize_t CallbackDataSource::readAt(off64_t offset, void* data, size_t size) { 51 if (mMemory == NULL) { 52 return -1; 53 } 54 55 // IDataSource can only read up to mMemory->size() bytes at a time, but this 56 // method should be able to read any number of bytes, so read in a loop. 57 size_t totalNumRead = 0; 58 size_t numLeft = size; 59 const size_t bufferSize = mMemory->size(); 60 61 while (numLeft > 0) { 62 size_t numToRead = std::min(numLeft, bufferSize); 63 ssize_t numRead = 64 mIDataSource->readAt(offset + totalNumRead, numToRead); 65 // A negative return value represents an error. Pass it on. 66 if (numRead < 0) { 67 return numRead; 68 } 69 // A zero return value signals EOS. Return the bytes read so far. 70 if (numRead == 0) { 71 return totalNumRead; 72 } 73 // Sanity check. 74 CHECK((size_t)numRead <= numToRead && numRead >= 0 && 75 numRead <= bufferSize); 76 memcpy(((uint8_t*)data) + totalNumRead, mMemory->pointer(), numRead); 77 numLeft -= numRead; 78 totalNumRead += numRead; 79 } 80 81 return totalNumRead; 82} 83 84status_t CallbackDataSource::getSize(off64_t *size) { 85 status_t err = mIDataSource->getSize(size); 86 if (err != OK) { 87 return err; 88 } 89 if (*size < 0) { 90 // IDataSource will set size to -1 to indicate unknown size, but 91 // DataSource returns ERROR_UNSUPPORTED for that. 92 return ERROR_UNSUPPORTED; 93 } 94 return OK; 95} 96 97} // namespace android 98